Ultrafast dynamics of reversibly photoinduced neutral-ionic transition in quasi-one-dimensional organic crystal tetrathiafulvalene-chloranil

We report that the phase transition between neutral and ionic phases (N-I transition) in the single crystal of tetrathiafulvalene-chloranil (TTF-CA) can be triggered by pulsed laser excitation with 80 femto-second pulse width. Irradiation with the pulsed laser light of which photon energy is 1.55eV can drive the phase changes in both I-to-N and N-to-I directions. We also report the excitation photon energy dependence of the N-I domain-wall dynamics.